JPH0229770A - Image forming device - Google Patents

Abstract

PURPOSE:To make uniform the temperature distribution between heating and pressurizing rollers when carrying out the copying action by pushing the printing button for the first time by making the paper feeding interval longer before a specified number has been finished copying, and executing the copying action at the normal paper feeding interval after the finishing of copying. CONSTITUTION:The warming up after the connection of an electric power source, is carried out without rotating the heating roller 41 and the pressurizing roller 45 of a fixing device 28, but by only turning on a fixing heater lamp 44, and completing when the roller 41 is detected to have reached a target fixing temperature by a fixing thermistor 48, to assure silence during a warming up. After that, when the printing button is pushed for the first time to carry out the copying action, that is to say first thing in the morning, the paper feeding interval is made longer until a specified number of copies have been finished copying, and carrying out the copying action with normal paper feeding interval after the copying is completed, making uniform the temperature distribution between the two rollers by the heat conduction generating from the rotation of the roller 41 and the roller 45, which is in contact with it, while copying paper is not fed, assuring good fixability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus, and particularly to an image forming apparatus that is designed to ensure quietness during warming up after turning on the power, and good fixing performance during the so-called first copying operation in the morning. This is what I did.

``Prior Art'' Heat roll fixing is a common fixing method for fixing toner images transferred onto copy paper, and in the early stage of so-called warming up after power is turned on, the heating roller and pressure roller are A fixing means is disclosed in Japanese Patent Publication No. 61-31, in which both rollers are kept in a non-rotating layer, and when the surface temperature of the heating roller reaches a predetermined temperature, both rollers are rotated together for a certain period of time.
No. 462.

This fixing means was developed to speed up the rise in surface temperature of the roller during warm-up and to perform the subsequent fixing well.

Further, a fixing means that reduces the copying speed when the surface temperature of the fixing roller drops below a predetermined temperature during continuous copying is also known from Japanese Patent Laid-Open No. 143067/1983.

This fixing means is designed to perform the copying operation without interrupting even if the fixing temperature drops below a predetermined temperature during continuous copying.

``Problem to be Solved by the Invention'' However, in the former fixing means described above, when the surface temperature of the heating roller rises to a predetermined temperature during warming up after the power is turned on, from that point on, the heating roller rotates together with the pressure roller. Due to heat conduction to the pressure roller, when the surface temperature of both rollers reaches the fixing target temperature, the rotation of both rollers is stopped and warming-up is completed. A so-called preliminary rotation of both rollers is started, which may surprise the user. In addition, the sound of rotation of both rollers during copying standby poses a psychological burden on the user, causing inconvenience in use, such as increasing irritation.

The latter fixing means prevents the continuous copying operation from being interrupted due to a drop in the fixing temperature, and ensures quietness during warming up, and also during the first copying in the morning after warming up is completed.
This was not a solution for ensuring good fixing properties.

The present invention has been made with attention to the above-mentioned points, and provides an image forming apparatus that can ensure quietness during warming up after turning on the power, and can also ensure good fixing performance during so-called first copying in the morning. The purpose is to

"Means for Solving the Problem" The specific means for achieving the above-mentioned object includes a heating roller having a built-in heating means, a pressure roller that rotates in contact with the rotationally driven heating roller, and a heating roller. In an image forming apparatus equipped with a fixing means comprising a temperature detecting means for detecting the temperature of the heating means, and a temperature controlling means for controlling the heating means based on a temperature detection signal, both rollers of the fixing means are rotationally driven when the power switch is turned on. Warming-up is completed by detecting a predetermined temperature by the temperature detecting means by driving only the heating means, and when the first copy start command signal is input after the warming-up is completed, a predetermined number of copies are made. The present invention is characterized by being provided with a copying control means that widens the paper feeding interval until the end of copying, and performs the copying operation at the normal paper feeding interval after the end of the copying. The present invention is characterized in that the copying control means slows down the copying system speed until the copying is completed, and then returns to the normal copying system speed to perform the copying operation.

"Operation" According to the above-mentioned specific means, warming-up after power is turned on is performed by driving only the heating means built into the heating roller without rotating the heating and pressure roller, and when the first copy start command signal is sent. When is input, the paper feed interval is increased until the predetermined number of sheets have been copied, and after that copy is completed, the paper feed interval is increased at the normal paper feed interval.
A copying operation is performed.

According to another specific means, the copying system speed is slowed down until a predetermined number of copies are completed, and after the copying is completed, the copying operation is performed to return to the normal copying system speed.

Embodiment An embodiment of the present invention will be described with reference to the accompanying drawings in an embodiment using a copying machine as an image forming apparatus.

FIG. 1 shows a schematic sectional view of a copying machine which is an image forming apparatus according to the present invention.

The copying mechanism of the copying machine main body 1 is similar to that of a conventional electrophotographic copying machine. A photoreceptor drum 2 that can be rotated in a counterclockwise direction is disposed in the center of the copying machine body 1, and a main eraser lamp 3. Electrostatic charger 6, developing device 7. Transfer charger8. Transfer paper separation charger9. Blade type cleaner device 1
0 etc. are arranged sequentially. The photosensitive drum 2 is a drum having a photosensitive material (e.g., selenium) on its surface, and is irradiated with light by an eraser lamp 3 and charged by passing through a charging charger 6 for each copy, and is then charged as described below. Receives image exposure from the optical system. The motor M1 drives the photosensitive drum 2 and the like.

The optical system is arranged below the document platen glass 11 so as to be able to scan the document image. The optical system includes a light source 12, a first mirror 13. Second mirror 14. Third mirror 15. Projection lens 1
6. It is composed of a fourth mirror 17. The original image is captured by mirrors 13, 14, 15, .
17, it reaches the photosensitive drum 2.

On the left side of the copying machine main body 1, an automatic paper feed cassette 20a is arranged at the upper paper feed slot, an automatic paper feed cassette 20b is arranged at the lower paper feed slot, and a manual paper feed section 21 is arranged at the upper part. Automatic paper feed cassette 20a.

The copy paper in 20b or the manual paper feed section 21 is selectively fed into the copying machine main body 1 by the respective paper feed rollers 22 and 23, passes through each conveyance port-ra pair 24 and 25, and is pressed into a crimped state. It is conveyed to the timing roller 26 located at -
I will wait for a while.

At the time of transfer, the copy paper fed by the timing roller 26 comes into close contact with the photoreceptor drum 2 in the transfer section, and the toner image is transferred by the corona discharge of the transfer charger 8, and then the toner image is transferred by the corona discharge of the separation charger 9 and the copy paper is The paper is separated from the photosensitive drum 2 by its own stiffness. Next, the copy paper is sucked onto a conveyor belt 27 equipped with a near suction means (not shown) and conveyed to the right as the belt 27 rotates clockwise. The toner image is melted and fixed by passing through a fixing device 28 consisting of a toner image. and,
It passes through a pair of discharge rollers 29 and reaches a tray 30 outside the copying machine main body 1.
Alternatively, it is discharged to a collating machine (not shown) or the like.

FIG. 2 is an enlarged side view of the fixing device 28.

Reference numeral 41 denotes an upper fixing roller which is a heating roller. A Teflon coating layer 43 is formed on the outer periphery of a metal hollow rotating shaft 42 in order to improve release properties, and a fixing heater lamp is provided inside the hollow rotating shaft 42. 44 is installed inside the heating means. 45 is a lower fixing roller which is a pressure roller,
A silicone rubber coating 4 is placed on the outer periphery of a solid metal rotating shaft 46.
7 is applied, and spring elasticity is applied to the shaft support portions at both ends to bring them into pressure contact with the upper fixing roller 41 to improve fixing performance.

48 is a fixing thermistor installed to detect the surface temperature of the upper fixing roller 41, which is a heating roller.

Reference numerals 49 and 50 indicate separation claws provided to prevent the copy paper from wrapping around the upper and lower fixing rollers 41 and 45.

FIG. 3 is a schematic control circuit diagram of the device of this embodiment,
/D converter built-in CPU has ACloo outlet.
When connected to the V power supply, the DC5, V power supply of the power supply circuit 61 starts regardless of whether the power switch 62 is on or off. When the power switch 62 is turned on, the main switch 7 of the switch matrix 64 is activated by the relay 63.
0 is turned on. 71 is a print button for inputting a copying operation start command. The switch matrix 64 includes various display sections 65, and the switch matrix 64
Inputs from the various switches constituting the CPU are time-divisionally input to the CPU using a decoder 66.

The temperature signal detected by the fixing thermistor 48 is input to the analog port of the CPU, A/D converted, and processed as temperature data, and information regarding the control of the copying machine is input to the other input ports.

Each output boat of the CPU has a main motor Ml of the copying machine main body 1, an electrostatic charger 6, and a transfer charger 8.
．． Drive switching transistors (not shown) are connected to the heater lamp 44 of the fixing device 28, the fixing device clutch that drives the developing device 7, the paper feed rollers 22 and 23 clutch, and the timing roller 26 clutch. Other outputs are sent out as control information for peripheral circuits.

FIG. 4 is a flowchart showing an outline of the main routine of the CPU that controls the entire copying machine.

When the CPU is reset and the program is started, in step Sl (hereinafter the step is omitted), initialization of the CPU such as clearing the RAM, setting of various registers, etc., and initial setting to put the copying machine into the initial mode are performed.

In S2, an internal timer built into the CPU and preset with one routine time in the initial setting is started, and in the following steps 83 to S6, the key, switch-on cultin, temperature adjustment routine, copy operation routine, Each of the subroutines of the other processing routines is sequentially called, and when all subroutine processing is completed, the first routine is terminated after waiting for the end of the initially set internal timer (S7).

The time length of this one routine is used to count the various timers used in each subroutine.The various timer values can be used to judge the end of the timer depending on how many times this one routine has been counted. can.

FIG. 5 is a flowchart showing the temperature adjustment routine.

First, in step 5200, it is determined whether or not the power switch 62 is in the on state. If it is in the off state, the answer is No and the flag F2
is set to "1", and the flag F1 is reset to "0" at 5220. The flag F2 is a flag that stores that the power switch 62 is turned off, and the flag F1 is a flag that stores that the warming-up is completed and the target fixing temperature 19
This is a flag indicating that the temperature control state Fl (hereinafter referred to as temperature control state) is 0°C.

Next, the process advances to 5250, where the fixing heater lamp 44 is turned off and this subroutine ends.

In this case, even when the power is off, the CPU is backed up by a 5V DC power source, as explained in the control circuit above.

In step 5200, if the power switch 62 is in the on state, the answer is YES and the process proceeds to step 5230, where it is determined whether the detected temperature TU of the fixing thermistor 48 is the fixing target temperature 190° C. or higher, and if it is 190° C. or higher, the answer is YES. At 8240, the flag F1 is set to "1", and at 5250, the fixing/fixing heater lamp 44 is turned off. Also, in the above 5230, TU is 19
If the temperature is lower than 0° C., the process advances to 8260, turns on the fixing heater lamp 44, and ends this subroutine.

FIG. 6 is a flowchart showing the copy operation routine.

First, in step 5300, it is determined whether the flag F1 is set to "1" or not. If F1=0, that is, the power switch 62 is off, or the power switch 62 is on and warming-up is complete. Since this is not the case, return and end this subroutine.

If flag F1 = 1, the copying can be started after the warming-up has been completed, and the process proceeds to step 5310, where it is determined whether the print button 71 is on edge (when the state of the switch changes from the off state to the on state). If it is on-edge, the answer is YES, and the process proceeds to 5320, where it is determined whether the flag F2 is set to "1". F2=
If it is 1, it indicates that the print button 71 is pressed for the first time after the power switch 62 is turned on, that is, in the morning, and the process advances to 5330 to determine whether or not the predetermined number of copies have been completed. If it is not finished, select No and 53
Set the paper feed interval timer to the second timer at 40 and set the paper feed interval timer to the second timer at 5370.
Then, the image forming operation subroutine is called and copying is started.

If the predetermined number of copies have been completed in 5330,
Proceed to 5350, set the paper feed interval timer to the first timer, proceed to 5360, reset flag F2 to "0",
At 370, a subroutine for image forming operation is called to start copying.

The timer value of the first timer to which the paper feed interval timer is set defines the paper feed interval in the case of normal copying operation, and the timer value of the second timer is set to specify the paper feeding interval in the case of normal copying operation. The paper feeding interval is too high.

Specifically, when copying A4 size copy paper at the same size and passing it horizontally, when the paper feed interval is set to the first timer,
The distance between the rear end of the copy paper and the leading edge of the next copy paper is 200 mm,
In the case of the second timer set, the same value is <300 mm.

On the other hand, if the flag F2=0 in 5320, the current print button 71 is pressed after the power switch 62 is turned on.
This indicates that the image forming operation has already been performed by the time the button is pressed, and the process immediately advances to 5370 to start the image forming operation.

If the print button 71 is not on-edge at 5310, the process goes to 5380, and if the image is currently being created, it is determined whether or not the image forming operation for the set number of sheets has been completed.If it is not completed, the process goes to 5320. Execute each step of ~5370, and if the image forming operation for the set number of sheets is completed, YES'''
The process advances to cS390 to end the image forming operation.

In the copy operation routine, the power switch 62
During warming-up after turning on, only the fixing heater lamp 44, which is a heating means, is turned on without rotating the heating roller 41 and pressure roller 45 of the fixing device 28, and the heating roller 41 reaches the fixing target temperature of 190° C. This is completed when the fixing thermistor 48 detects this, ensuring quietness during warming up. After that, the print button 71 is pressed for the first time and the copying operation is performed in the morning.
In this case, the paper feeding interval is increased until the copying of a predetermined number of sheets is completed, and after the copying is completed, the copying operation is performed at the normal paper feeding interval, and the copying paper is brought into contact with the heating roller 41 while it is not being fed. The heat conduction caused by the rotation of the pressure roller 45 equalizes the temperature distribution between both rollers, thereby ensuring good fixing performance. During this time, the fixing heater lamp 44 built into the heating roller 41 is controlled on and off by a temperature adjustment routine to maintain the fixing target temperature.

"Other Embodiments" FIG. 7 is a flowchart showing another copy operation routine.

This flowchart shows the sixth step explained in the above embodiment.
In the flowchart shown in the figure, 5340°5350,5
Since each step in 370 is changed and the order of steps in 8360 is changed, the same steps are given the same step number and the explanation will be omitted, and only the different parts will be explained.

Determine flag F2 at 5320, and if F=O, 536
It jumps to 0a and starts a copying operation in a first copying mode which will be described later. Furthermore, if F2=1, this indicates that the print button 71 is pressed for the first time after the power switch 62 is turned on, so the process advances to 8330, where it is determined whether or not a predetermined number of copies have been completed. If not, NO
Then, in 5340a, the image forming operation is started in the second copy mode.

Also, if the predetermined number of copies have already been completed in 5330, the answer is YES, and the process proceeds to 5350a, where the flag F2 is set to "0".
After resetting to 5360a, the image forming operation is started in the first copy mode.

The first copy mode is for copying at the system speed of normal copying operations, specifically the speed at which A4 size copy paper is passed horizontally during full-size copying, at 200 am.
It is about l see. The second copy mode is one in which the system speed is slower than the first copy mode, specifically about 150 aml sec under the above conditions. In the second copy mode, the system speed is reduced through comprehensive adjustment of the scanning speed of the scanning system, the paper feeding interval, the amount of light emitted from the exposure lamp, etc.

Since the image forming operation is executed in each copy mode, the step 8370 in the flowchart of FIG. 6 can be omitted.

In this embodiment, the quietness of the warming-up is ensured, and in the so-called first copying operation in the morning after the completion of the warming-up, the system speed for copying a predetermined number of sheets is slowed down, so that the fixing device 28 is operated at a lower speed. Heat conduction from the heating roller 41 to the pressure roller 45 is relatively accelerated, promoting uniformity of temperature distribution between both rollers, and ensuring good fixing performance.

Further, in each of the above-described embodiments, the predetermined number of sheets set for the first copying operation after completion of warming-up is about 10 sheets when A4 size copy paper is passed horizontally.

It should be noted that the image forming operation described in each of the above embodiments is completed and the first image forming operation is completed. Since the subroutines of the second copy mode are outside the scope of the present invention and their basic operations are well known, their explanations will be omitted.

"Effects of the Invention" As clarified in the explanation of the specific means and effects, the present invention provides warming-up after turning on the power by driving only the heating means of the fixing means, so that unexpected heating can occur. Also, warming up can be performed quietly without the pressure roller starting to rotate and surprising the user, and heat is conducted to the pressure roller that contacts the heating roller when it is not rotating. It is possible to shorten the time interval until the temperature of both rollers becomes uniform, and in the first copying operation that starts after the warm-up is completed, the paper feeding interval can be increased or the copying operation can be continued until a predetermined number of copies have been completed. By slowing down the system speed, the speed of heat conduction from the heating roller to the pressure roller becomes relatively faster, which further promotes uniformity of temperature distribution between both rollers and ensures good fixing performance. There is an effect.

[Brief explanation of the drawing]

The accompanying drawings illustrate embodiments of the present invention, in which FIG. 1 is a schematic sectional view of the copying machine main body 1, which is an image forming apparatus, FIG. 2 is an enlarged sectional view of the fixing device 28, and FIG. 3 is a schematic control circuit diagram. , FIG. 4 is a flowchart of the main routine, FIG. 5 is a flowchart of the temperature adjustment routine, FIG. 6 is a flowchart of the copy operation routine, and FIG. 7 is a flowchart showing another copy operation routine. 28, ,Fixing device, 41, ,Heating roller, 45
,,,pressure roller, 48. ,,fixed thermistor,6
2,,,@source switch, 71,,,print button. Diagram

Claims (2)

[Claims] (1) A heating roller with a built-in heating means, a pressure roller that rotates in contact with the rotationally driven heating roller, a temperature detection means that detects the temperature of the heating roller, and a temperature detection signal that detects the heating roller. In an image forming apparatus equipped with a fixing means including a temperature control means, when a power switch is turned on, only the heating means is driven without rotationally driving both rollers of the fixing means, and the temperature detection means detects a predetermined temperature. At the same time, when the first copy start command signal is input after the completion of the warming-up, the paper feeding interval is increased until a predetermined number of copies have been completed, and after the completion of the copying, the normal paper feeding interval is maintained. An image forming apparatus comprising a copy control means for performing a copy operation. (2) The copying control means is a copying control means that slows down the copying system speed until a predetermined number of copies are completed, and then returns to the normal copying system speed and performs the copying operation. The image forming apparatus according to claim 1.